I'm a bit embarrassed to pose the question, but I truly don't know the answer. That said, here we go: What in the world is a CAUCUS, a nominitive method used by, in addition to Iowa, Wyoming, Louisiana, Minnesota, Montana, Colorado, North Dakota, Alaska, Nevada, Hawaii, Maine, West Virginia, Washington State, and Kansas???
Well, according to the Dorsey Dictionary of American Government and Politics, the caucus is...
"...a private meeting of political party members in order to seek agreement on a common course of action, to select delegates for a state or national nominating convention, and so on. The caucus was an early method of selecting presidential candidates before its replacement by party conventions (and for nominating state and local candidates) rests of a series of party meetings that begin at the precinct level and extend to the state convention. The first round caucuses are especially important, for they often establish the share of delegates awarded to each candidate." (pg. 86)."
"...Meeting on members of a political party in order to make decisions on policy or to select candidates."
"Until 1824 candidates for the presidency and vice presidency of the United States were selected by the congressional caucus of each party. Public opposition to what was considered a secretive, elitist process and the growth of mass political parties resulted in the establishment of national nominating conventions, but caucuses are still used in some states, such as Iowa, as the first step in selecting delegates to the national meetings."
"Those who support the the use of caucuses assert that they encourage participatory democracy by requiring voters to take time out for the process and to debate each other face-to-face. Those who oppose their use argue that most caucuses are dominated by individuals with strong ideological stands that may not reflect the thinking of rank-and-file party members." (pg. 84).
A very good article, comparing the two nominating systems is accessible through SPL's EBSCO Database. To view Thomas Marshall's Turnout and Representation: Caucuses Versus Primaries from the American Journal of Political Science, (Feb78, Vol. 22 Issue 1, p169, 14p), click here (library card and PIN required for viewing).
And, if that weren't enough, the official Web site of the Iowa Caucuses is a pretty good place for answers: http://www.iowacaucus.org/iacaucus.html
California will nominate its candidates on February 5, 2008. The Central Library will have election guides and voter registration forms available on Thursday, the 3rd, of January. All literature will be placed at service desks on the 1st, 2nd and 3rd floors.